Dental tool.



F. WLTRABOLD & J. T. KNOX.

DENTAL TOOL.

APPLICATION FILED 05c. 11. 1914.

1,158,872. Pat nted Nov. 2, 1915.

i i J Em! j INVENTORS By Attorneys,

FRANK W. TRABOIJD AND JOHN T. KNOX, OF NEW YORK, N. Y.

DENTAL TOOL.

Specification of Letters Patent.

Patented Nov. 2, 1915.

Application filed December 17, 1914. Serial No. 877,717.

To all whom it may concern Be it known that we, FRANK W. TRABOLD and JOHN T. KNOX, citizens of the United States of America, residing in the borough of Brooklyn, county of Kings, city and State of New York, have invented certain new and useful Improvements in Dental Tools, of which the following'is a specification.

The invention is particularly directed to a dental tool for removing the dowel pins (called posts) used in attaching crowns to roots. Vhen a crown has become broken or has been removed for any other reason, the post by which it was connected to the root (usually by cement or the like) is often difficult to extract from the root, and various tools have been proposed for this purpose.

The present invention relates to an improved device of thischaracter which can be easily operated by one'hand, and in which the removal of the post is accomplished without pain to the'patient.

The invention in its preferred form comf prises a pair offorceps adapted to engage the protruding end of the post, means for holding the forceps tightly gripping the post, and compensating means for exerting a balanced thrust against the top of the root whereby to pull out the post. The operator closes the forcep jaws upon the post and locks or clamps them together, and then by closing a lever arm or handle exerts a thrust through the compensating means against the top of the root which pulls out the post.

In the drawings, Figures 1 and 2 are respectively side and edge views of the tool in its preferred form; Fig. 3 is a fragmentary side view partly in section showing the extracting operation; Fig. l is a similar view showing the tool at the end of the extracting operation; Fig. 5 is an edge view in midsection showing the parts in the same position as Fig. d; Fig. 6 is a view corresponding to Fig. 1 showing a modified construction; Fig. 7 is a sectional view showing the construction of Fig. 6.

Referring to the drawings, A and B are the handles of a pair of forceps pivoted on a pin C and having jaws a 6 adapted to grip the protruding portion of the post. hen the forceps are closed together to grip the post, it is necessary to have some means for holding them so closed, and for this purpose we provide preferably a sliding band D which can be slipped along a portion 0 (Z of the handles where they are slightly out of parallel, so that as it is slipped away from the pivotal point it acts to draw the jaws together by an application of the wedge principle.

In order to make the extracting operation as nearly painless as possible, it is customary in tools of this class to exert the reacting thrust against the end of the root, and for this purpose it iscustomary to apply one or two thrust pins to bear upon the root. These pins in the improved tool are lettered E E, being preferably directed as close together as practicable at their bearing ends, while their main or body portions are shown as formed as round pins 6 c which slide through some suitable guide and are connected at their opposite ends to a thrust lever F which is pivoted atf to one of the jaws, and is shaped so that its long arm serves as a handle adapted to fold against one of the forcep arms A or B, while its short arm projects into the space between tion that the reacting thrust during the extracting operation is balanced or compensated, so that in the case of any inequality of level of the top of the root, the'thrust against the root shall be uniform and without exerting any tilting tendency. For this purpose the connection between the thrust pin and the extracting lever is accomplished through an equalizing lever or rock piece G, best shown in Fig. 5, which is connected at its ends to the thrust pins and at its middle to the lever F, the latter connection being best made through a stirrup H which is pivoted to the short arm of the lever F by one pin, and to the middle of the equalizer G by another pin at right angles thereto.

, This construction permits either pin to proinc plane of the aws a b is at right angles'to the direction of the. row of teeth. Hence to enable the tool to be introduced into the space between the teeth, it is desirable as before stated to bring the bearing ends of the pins E E as close together as will admit the post andthe working ends of the jaws between them, in order that the tool may be intro duced within the width of the narrowest tooth.

The details of construction of the tool may be considerably varied without departing from the invention. For example Figs. 6 and 7 show a modified construction illustratingcertain practicable variations. In this 7 case the jaws a b are made somewhat longer,

the push pins E E are made shorter and nearly Straight and are guided in a projec tion 9 from thejaw b, and the lever F is pivoted to this same jaw, the parts G and H v tool first described being designed only for use with front teeth (the use of crowns supported upon dowel posts being mainly limited to front teeth).

While we have shown and described several forms of the invention, it will be understood that we do not wish to be limited thereto, since various changes may be made therein without departing from the spirit of the invention. Y

We claim as our invention V 1. A pair of forceps having a pair of push Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

pins, means for exerting a thrust against the push pins, and equalizingmeans for distributlng the thrust to such push pins.

an pair of forceps having a pair of push plns, means for 'exertlng a thrust against the push pins, and an equalizing lever for distributing such thrust to the push pins.

3. A pair of forceps having push pins, and a thrust lever pivoted to the forceps and having an equalizing engagement with the push pins.

4:. A pair of forceps havlng a pair of push pins arranged close against opposite sides of their jaws, and athrust lever pivoted to 1 the forceps, connected to said push pins, and movable against the forcep handles to exert a thrust to protrude the push pins.

5. A'pair of forceps' having push pins, a thrust lever pivoted to the forceps, and an thrust lever engaging the middleof: said J equalizing lever,

7. In a post puller, the combination of I means adapted to grip the'post, and a thrust device adapted to bear againstthe tooth at a plurality of points, the post pullerhaving 7 equalizing means adapted todistribute the thrust between such points. 7 In witness whereof, we have hereunto scribing witnesses.

' 1 FRANK w. TRABOLD. JOHN T. KNOX.

Witnesses:

E. G. MYERS, hnnn WHITE.

Washington, D. C.

signed our names in the presence of two subr 

